1. Field of the Invention
The present invention relates to a sealing member residing inclusively between two members having opening portions, which enables the opening portions of such members to be communicated, while seals them from the outside, and a connecting structure provided with such sealing member. The invention also relates to a liquid discharge recording head that records by discharging recording liquid from discharge ports.
2. Related Background Art
The liquid discharge recording method (ink jet recording method), in which droplets of recording liquid (ink) or the like, are discharged from the discharge ports (orifices) of a liquid discharge recording head, is the so-called non-impact recording method that makes high-speed recording possible, and also, makes recording possible on various recording mediums with the advantage that noises are not practically generated at the time of recording. As a result, the liquid discharge recording apparatus that mounts the liquid discharge recording head is widely adopted as recording means for a printer, a word processor, facsimile equipment, a copying machine, and a mailing machine, among some others.
As the typical example of the liquid discharge recording head of the kind, there is one that uses electrothermal converting element for heating recording liquid to bubble, thus discharging liquid droplets from fine discharge ports to a recording medium for the execution of recording. Then, as the liquid discharge recording head, it is generally practiced to form a structure with the recording unit that forms liquid droplets, and the recording liquid storing unit that supplies recording liquid to the recording unit.
With reference to FIG. 17 and FIG. 18, the conventional liquid discharge recording head will be described. FIG. 17 is a partially broken perspective view that shows the recording unit of the conventional liquid discharge recording head. FIG. 18 is an exploded perspective view.
As shown in FIG. 18, the liquid discharge recording head is structured by bonding the recording unit 1140 and the recording liquid storing unit 1130.
As shown in FIG. 17, for the recording unit 1140, the recording element base plate 1107 provided with the recording element 1106 that serves as the energy generating member for discharging liquid is die bonded on the supporting base plate 1110, which is formed by aluminum, ceramics, or the like. On the recording element base plate 1107, there are provided shift registers for driving use, and wiring patterns, although not shown, besides the recording element 1106. These are incorporated together with the recording element 1106 on the recording element base plate 1107 in advance by use of the silicon formation technologies and techniques. To the recording element base plate 1107, the ceiling plate 1100 having pressed portions that become liquid flow paths 1103 and a liquid chamber 1104 is fixed by means of a flat spring 1105 or other pressure means or bonding means, such as bonding agent. In this manner, the liquid flow paths 1103 and common liquid chamber 1104 are partitioned. Further, the flow path formation member 1120 is arranged on the upper face of the ceiling plate 1100, which connected with the supply port 1122, thus supplying recording liquid to the common liquid chamber 1104 in the ceiling plate 1100. Inside the flow path formation member 1120, flow paths of recording liquid are formed, and a porous member 1121 is bonded in the flow paths on the side opposite to the bonding portion to the ceiling plate for trapping impurities contained in recording liquid. Also, an orifice plate 1101 is aligned and bonded to the end face of the ceiling plate 1100 and the recording element base plate 1107. The orifice plate 1101 is provided with fine discharge port groups (orifice groups) 1102 for discharging liquid droplets.
To the supporting base plate 1110, the wiring base plate 1108, which makes electric connection with the liquid discharge recording apparatus main body, is bonded besides the recording element base plate 1107. The recording element base plate 1107 and the wiring base plate 1108 are electrically connected by use of wire bonding, lead bonding, or the like. For the wiring base plate 1108, contact pads (not shown) are formed to electrically connect it with the liquid discharge recording apparatus main body.
On the other hand, as shown in FIG. 18, the recording liquid storing unit 1150 is provided with the frame member 1130 having a recording liquid storing chamber (not shown) that contains recording liquid therein, which serves as the housing to support the recording unit 1140. The frame member 1130 that forms the principal part of the recording liquid storing unit 1150 is structured with the frame member main body 1130a and the frame member cover 1130b. Then, the frame member cover 1130b is bonded to the frame member main body 1130a by means of ultrasonic welding or the like on the plane that faces the connecting portion of the recording unit 1140. In this way, the recording liquid storing chamber is formed inside the frame member 1130.
Then, the recording unit 1140 is positioned and fixed to the frame member 1130 by bonding means, such as screws 1131, bonding agent, or the like. There is provide a predetermined gap for the bonding portion between the frame member 1130 and the recording unit 1140, and the gap is completely closed by sealing applied with the sealant or bonding agent, which flows into the gap to be solidified in it.
In the liquid discharge recording head, recording liquid stored in the recording liquid storing chamber is supplied to the liquid flow paths 1103 through the flow path formation member 1120 and the ceiling member 1100.
Here, the liquid discharge recording head is in the mode in which a single recording element base plate 1107 is die-bonded to the supporting base plate 1110. However, there is another mode in which plural recording element base plates 1107 are die-bonded to the supporting base plate 1110. Also, there are the liquid discharge recording apparatus of the mode in which is mounted only one liquid discharge recording head having single recording element base plate 1107 assembled thereon, and the liquid discharge recording apparatus of the mode in which plural liquid discharge recording heads are mounted.
In the liquid discharge recording head that uses electrothermal converting element as the recording element 1106, the electrothermal converting element is provided inside the liquid flow path 1103, and then, when electric pluses carrying recording signals are applied thereto, thermal energy is given to recording liquid. With the phase changes of recording liquid at that time, recording liquid bubbles (film boiling occurs), and the bubbling pressure is utilized for discharging recording liquid droplets. Here, in the case of the liquid discharge recording head that uses electrothermal converting element as the recording element 1106, there are the method in which recording liquid is discharged in parallel to the recording element base plate 1107 having the electrothermal converting element is arranged therefor (that is, the edge shooter method: see FIG. 17), and the method in which recording liquid is discharged vertically to the recording element base plate having the electrothermal converting element arranged therefor (that is, the side shooter method: not shown).
Also, FIG. 19 is an exploded perspective view that shows the other conventional liquid discharge recording head. The frame member 2202 of the liquid discharge recording head that forms the principal part of the recording storing unit thereof is structured by bonding the frame member main body 2201 and the frame member cover 2204 by ultrasonic welding after the insertion of the porous member 2203. Then, inside the frame member, a recording liquid storing chamber (not shown) is formed. To the surface of the frame member 2202 on the opposite side of the bonding face of the frame member cover of the frame member main body 2201, there is connected the recording unit 2100 that forms liquid droplets, and recording liquid can be supplied from the recording liquid storing unit to the recording unit 2100. More specifically, the cylindrical tube that extends from the recording unit 2100 is fitted into the opening portion of the frame member main body 2201, and then, on the circumference of the cylindrical tube, the rubber sealing member, which is so-called O-ring 2117 formed in an arc having a circular section, is arranged to effectuate connection, while securing the sealing capability.
In recent years, for the liquid discharge recording head, there have been in progress the higher discharge that increases discharge frequency per unit time and the multiple nozzle arrangement that increases the number of discharge nozzles (discharge ports) in order to obtain the higher recording performance, which makes it possible to provide highly precise recording at higher speed. Along with this, it is required to provide a countermeasure such as to increase the capacity and the sectional area of flow path corresponding to the increased amount of discharging liquid for the liquid flow path in the recording unit and the recording liquid storing chamber in the recording liquid storing unit, as well as in the portion that connects the recording unit with the recording liquid storing chamber. If the flow path sectional area is increased in the connecting portion, it is inevitable to make the closing mechanism larger, which should be provided on the circumference of the connecting portion in order to prevent the liquid leakage from or the mixture of the air in such portion.
On the other hand, the space saving and the cost reduction are required, and the need for downsizing of the liquid discharge recording head is more increasingly. Particularly, for the liquid discharge recording apparatus, for which plural liquid discharge recording heads are arranged for use, it is prerequisite that the liquid discharge recording head is made smaller and thinner in the arrangement direction thereof.
As in the case of the conventional liquid discharge recording head described earlier, where the connecting portion between the recording unit 2100 and the frame member 2202 of the recording liquid storing unit is sealed by the rubber sealing member, which is so-called the O ring 2117 (see FIG. 19), it is extremely difficult to cope with both making the sectional area of the connecting flow path larger along with the increased amount of discharge liquid, and making the liquid discharge recording head smaller and thinner simultaneously. In other words, the diameter of the O-ring 2117 should be made larger corresponding to the increased sectional area of the liquid flow path, which leads to making the liquid discharge recording head larger accordingly. Also, for this structure, the cylindrical tube is fitted into the opening portion as described earlier so as to prevent the leakage of recording liquid and the mixture of the air by the provision of the O-ring 2117, which is buried on the circumference of the cylindrical tube. In order to make the sealing capability thereof reliable, the inner circumference of the O-ring 2117 should be fit into the outer circumference of the cylindrical tube tightly, and the opening portion should be small enough so as to be clogged by the inner circumference of the O-ring 2117. The cylindrical tube and the O-ring 2117 should be manufactured in good precision, respectively, so that a precise work can be carried out in the assembling process.
Further, if the O-ring 2117 should be damaged or some foreign substance should be put between them unexpectedly due to some causes, such as variations in manufacturing steps for the structure in which the O-ring 2117 is used, sealant or bonding agent is not applied exactly to the circumference of the liquid flow path when the structure needs the application of sealant or bonding agent. As a result, the leakage of recording liquid and the mixture of the air take place take place in such imperfect portion to make it impossible to anticipate the performance as desired or to stain the interior of the liquid discharge recording apparatus main body eventually or in the worst case, short-circuit or the like is induced in the electric systems. Inversely, therefore, there is a need for manufacturing and assembling each of the components in extremely high precision.
On the other hand, in the case where the recording unit 1140 and the recording liquid storing unit 1150 are connected by sealant or bonding agent without using any sealing member (see FIG. 18), there is no need for making the size of the liquid discharge recording head larger considerably. However, there is a need for a time required for the sealing or bonding process, and a waiting time for keeping them in tact until sealant or bonding agent is solidified. As a result, work becomes complicated and the time required for completing work becomes longer. Also, the number of products on process (half-finished products on the way of manufacture) is increased, leading to the higher production costs. Also, the sealant or the bonding agent thus used tends to be fixed too strongly. Therefore, the dismantle work at the time of discarding the recording apparatus becomes inferior to the case where the sealing member is used. The bonded portion cannot be dislocated easily to make recycling inconvenient, hence presenting problem in terms of environmental protection.
For the aforesaid conventional liquid discharge recording head, the frame members 1130 and 2200 that form the principal part of the recording liquid storing unit are structured with two parts, the main body (frame member main body) 1130a and 2201, and the cover (frame member cover) 1130b and 2204. Now, the reasons are given below. For example, the structure shown in FIG. 19 that uses the O-ring 2117 needs the opening portion large enough to fit with the cylindrical tube of the recording unit 2100 for the frame member 2202 of the recording liquid storing unit. On the other hand, in order to retain the large amount of recording liquid as much as possible, almost entire body of the recording liquid storing unit is arranged to be the recording liquid storing chamber. As a result, the sectional area of the opening portion is, usually, made smaller than the sectional area of the recording liquid storing chamber. Then, it becomes necessary to arrange the drawing direction in the molding process to be opposite to the direction toward the opening portion, and in order to make drawing from the mold possible, the portion of the frame member 2201 on the side opposite to the opening portion should be arranged to open entirely after all. Then, in order to structure the recording liquid storing unit provided with the recording liquid storing chamber, the frame member cover 2204 is bonded to close the totally open surface of the frame member 2201 (the portion thereof on the side opposite to the opening portion). In this manner, the frame member 2202 is formed with the two members, the frame member main body 2201 and the frame member cover 2204. Also, for the structure shown in FIG. 18 that uses sealant or bonding agent, almost the entire body of the recording liquid storing unit 1150 is arranged to be the recording liquid storing chamber, and it is usually practiced to provide the opening portion, the sectional area of which is smaller the sectional area of the recording liquid storing chamber. Consequently, in the same way as described earlier, the frame member 1130 that forms the principal part of the recording liquid storing unit 1150 is formed by the two parts, the frame member main body 1130a and the frame member cover 1130b. The structures thus arranged present the drawbacks given below.
In other words, the frame member of the recording liquid storing unit should be made with plural parts, which makes it necessary to manufacture the respective parts by molding or the like, and bond them by use of ultrasonic welding or the like. This inevitably makes the production process complicated with increased numbers of half products, thus causing the production cost to be increased accordingly. Particularly, the recording liquid storing unit has the function to retain recording liquid in its interior. For that matter, there is a need for the complete prevention of the leakage of recording liquid to the outside, and the induction of the air outside into the interior thereof. Usually, when two parts are fused for bonding, the products with imperfect bonding are made in a certain probability as manufacturing errors unavoidably. Therefore, inspection is carried out after bonding to ascertain the bonding condition, and another process should be taken to remove defective products caused by such imperfect bonding. The addition of the inspection process results in the increase cost of production, and then, defective products are detected, the production cost of such products should be added to the final production costs, leading to a higher pricing of the finished product eventually. Also, the bonded part formed by plural components tends to be broken from the bonded portion, because stress is intensively given to the bonded portion if external shocks are added, thus making the strength of the bonded part weaker than the single part formed itself.
The problems that have been described above are caused by the structure of the frame member inevitably formed by two components, the frame member main body and the frame member cover due to the convenience of molding process, because the sectional area of the opening portion provided for the bonding portion of the recording liquid storing unit with the recording unit is smaller than the sectional area of the recording liquid storing chamber. Conventionally, there has been no structure in which the bonding portion of the recording unit is sealed exactly for the opening portion having the sectional area larger than the sectional area of the recording liquid storing chamber.
Now, therefore, the present invention is designed to aim at the provision of a sealing member capable of supplying recording liquid from the recording liquid storing unit, which is formed simpler than the conventional one, to the recording unit with a high sealing capability, and a connecting structure that contains such sealing member, as well as a liquid discharge recording head provided with such structure.
The present invention is characterized in that a sealing member, which exists inclusively between two members each provided with an opening portion for sealing both members from the outside, while enabling the opening portions of both members to be communicated, comprises a flat portion becoming the main body of the sealing member; a hole portion provided for the flat portion for enabling the opening portions of both members to be communicated; and ribs formed for both faces of the flat portion in the form of surrounding the hole portion and the opening portions of both members, and that the ribs of this sealing member include a first face-side rib formed on one face of the flat portion, and a second face-side rib formed on the other face of the flat portion in the symmetrical position and shape of the first face-side rib with the flat portion as the center. Here, it is preferable to provide the first face-side rib in plural number, and the second face-side rib also in the same number as that of the first face-side rib.
This sealing member is capable of sealing reliably with the ribs being smashed and deformed when being nipped by the two members. Particularly, with plural lines of ribs provided for one face, the reliability is enhanced significantly, because even if a part of ribs is made impossible to implement the sealing function due to some unexpected cause, the other ribs are able to implement the sealing function.
It may be possible to form each of the ribs to be essentially rectangular, and to be in a configuration to surround the opening portion. It may be possible to configure the rib to follow the outer shape of the flat portion. It is preferable to provide at least on one face of the flat portion a connecting portion for use of positioning on the inner side of the rib to effectuate positioning with respect to the member abutting against such face.
Another feature of the present invention is such that the connecting structure, which enables two members each provided with an opening portion to be communicated to make distribution of liquid possible, while sealing them from the outside, is provided with either one of the aforesaid sealing members that inclusively exists between both members, and
for the portions of both of the members facing such sealing member, connecting faces each abutting the ribs, are provided on the outer side of each of the opening portions, and the sealing member is held so as to keep the ribs in a state of being compressed between the connecting faces themselves of both members.
With the structure thus arranged, it becomes possible to form simply and at lower costs the structure that enables two members to be communicated to make the distribution of liquid possible, while sealing them from the outside in addition to the effects that has been described earlier. Particularly, then, the configurations and sizes of the bonding face and opening portions of the two members can be freely selected to a considerable extent, and the freedom of designing is enhanced to make wide and various utilizations possible.
For the connecting structure, the portions of both members that face the sealing member themselves are not necessarily provided connecting means to connect them with each other directly. The opening portions of both members themselves may be in the shapes and sizes different from each other. The hole portion of the sealing member may be in the shape and size different from any one of the opening portions of both members. In other words, it is possible to effectuate the bonding having a high sealing capability even without any tight connection, such as fitting of both members and the sealing member. Therefore, the bonding faces of both members and the shape and size of the sealing member can be selected freely to a considerable extent, while the dimensional precision needed for bonding with the secured sealing capability, that is, the precision of a product formation and assembling precision, can be eased considerably as compared with the conventional art. This makes manufacture easier, and reduces the generation of defective products.
It is preferable to provide at least on one face of the flat portion of the sealing member with a connecting portion for use of positioning on the inner side of the ribs surrounding said opening portion, and then, of the bonding faces of both of members on the side of the portion that faces the connecting portion for use of positioning, a portion being connected is provided to engage with the connecting portion for use of positioning. Here, the connecting portion for use of positioning is either one of a boss and a recessed portion, and the portion being connected is the other one of them.
Still another feature of the present invention is such that for the liquid discharge recording head, which comprises a recording unit for recording by discharging liquid droplets from discharge ports, and a recording liquid storing unit connected with the recording unit for supplying recording liquid, the recording unit is provided with a supply hole serving as an opening portion for supplying recording liquid, and the recording liquid storing unit is provided with a recording liquid storing chamber having one side portion serving as an opening portion, and then, the bonding face, which is provided with the supply hole of the recording liquid storing unit formed therefor by penetrating the face, and the bonding face, which is positioned on the opening portion of the recording liquid storing unit, are bonded through a sealing member having any one of the aforesaid structures, and the sealing member is held in a state where the ribs are nipped and compressed between the bonding face of the recording unit and the bonding face of the recording liquid storing unit.
With the structure thus arranged, the recording unit and the recording liquid storing unit can be bonded extremely simply by nipping the sealing member between both members, and along with it, the liquid discharge recording head can be manufactured easily at lower costs. Further, the recording unit and the recording liquid storing unit are bonded by use of snapping fits with the sealing member being nipped between them, but not adhesively bonded. Thus, while the sealing capability is kept, dismantling of the product after use can be performed with ease, and the structure makes recycling easier, and preferably adoptable in terms of dealing with the environmental problems, too. Also, the supply hole of the recording unit and the opening portion of the recording liquid storing unit, that is, the sectional area of flow path through which liquid flows, may be formed in various shapes, such as a circle, a polygon, so as to be configure it to follow the entire shape of the liquid discharge recording head. For the higher speed recording of the liquid discharge recording head, the flow path section in the form of rectangle can be easily expanded in such a manner that while the sorter side is left intact, only the longer side is made larger, for example.
The opening portion of the recording liquid storing unit is such that one side portion of the recording liquid storing chamber is totally open to the outside, and it is preferable to make the shape of the opening portion equal to the sectional shape of the recording liquid storing chamber. It is preferable to form the frame member, which is provided with the recording liquid storing chamber and serves as the principal part of the recording liquid storing unit, by a single member.
With the structure thus arranged, it is unnecessary to execute steps to bond plural components for the formation of the frame member. As a result, no steps are needed to inspect the bonding portions to make it possible to reduce the manufacturing costs of the product, and also, to curtail the number of half products (the half products on the way of manufacture), as well as to curtail the costs that may incur from the defective products. Here, the overall cost down is possible eventually. Also, a single member forms the structure, not by bonding plural members. The strength against external shocks is improved to enhance the reliability. Also, the flow path section on the connecting portion with the recording unit can be expanded to the maximum sectional area of the recording liquid storing chamber, thus making it possible to establish the same capability as the maximum capability of recording liquid supply provided for the recording liquid storing unit. In other words, it becomes possible to utilize the recording liquid storing chamber efficiently to the maximum. Thus, the recording liquid storing unit can be made smaller to the minimum dimensions required for the supply capability. Also, the area of the supply hole of the recording unit is set within a range of the recording liquid supply capability of the recording liquid storing unit, hence making it possible to attempt the optimization of the supply capability.
The recording unit is provided with the supply tube, for which the supply hole is formed to penetrate the bonding face of the recording unit, and the outer shape of the supply tube is smaller than the opening portion of the recording liquid storing unit and the hole portion of the sealing member. The supply tube may be inserted, not tightly but with a gap, into the opening portion of the recording liquid storing unit and the hole portion of the sealing member.
It is preferable to arrange a filter for the supply hole in order to remove mixed particles in recording liquid.
It is also preferable to provide at least on one face of the flat portion of the sealing member a connecting portion for use of positioning on the inner side of the ribs surrounding each of the opening portions, and also, to provide for the bonding faces of the recording unit and the recording liquid storing unit a portion being connected to engage with the connecting portion for use of positioning on the side of the portion facing the connecting portion for use of positioning, and then, to arrange the connecting portion for use of positioning by either one of a boss and a recessed portion, and the portion being connected by the other one of them. In this way, it becomes possible to prevent the positional deviation, twisting, or the like when the sealing member is nipped between the recording unit and the recording liquid storing unit, thus preventing liquid leakage or defect connection that may take place along such unfavorable event.
The recording unit is provided with a recording element base plate having plural recording elements arranged therefor, and a flow path formation member for supply recording liquid to the recording element base plate, and the bonding face with the recording liquid storing unit and the supply hole may be arranged for the flow path formation member.
In this respect, the sealing member and the connecting structure of the present invention are not only applicable to the connecting portion between the recording liquid storing unit and the recording unit, but also, applicable to the connecting portion where a sealing member inclusively exists between two member each having opening portion, in general, so as to seal such connecting portion from the outside, while enabling the opening portion of one member to be communicated with the opening portion of the other member.